Since earliest times, man has used energy in one form or another to heat his shelter. The energy employed has ranged from wood, coal, gaseous fuels, liquid fuels and electricity to solar energy. Solar energy in recent years has become increasingly important because it is unlimited in quantity and consumes no non-renewable natural resources. Fossil fuels, such as oil and gas, have become more scarce and costly. Electrical energy, while employed for many diverse purposes, including heating and cooling of habitable structures, is a secondary form of energy requiring some primary form of energy for its generation, such as fossil fuels or nuclear and hydroelectrical power. While hydroelectrical plants are used to generate electrical power using the energy of renewable resources, locations for such plants are finite and limited in nature and produce an expensive end product. Therefore, the one source of electrical power which is a form of renewable non-depleting energy comprises only a small fraction of the electrical energy generated in the United States. Nuclear power as an energy source for the production of electricity has been recently employed. Several years ago, nuclear energy was billed as being the method of producing electricity in a very economical manner; but because of the necessary controls which have been required for the nuclear functions and the control of the by-products, the plants using nuclear fuels have become exceedingly expensive and still may pose a severe hazard to all living things. For ecology reasons, total development of electrical power plants has been impeded, and world conditions have decreased our access to oil. This has, therefore, increased the need to utilize the relatively free energy of the sun.
Solar energy has, therefore, become a very important factor in the search for alternative sources of energy. Probably the principal limiting factor in the use of solar energy has been the lack of appropriate devices and mechanisms to efficiently capture and utilize the available radiant energy and light from the sun for use in retrofitting existing structures and for versatile employment in new construction.
During recent years, a number of mechanisms and devices for capturing the sun's energy and using it for heating and cooling have been developed. These include mechanisms which capture the radiant energy of the sun to raise the temperature of water or other fluids or air so that heat can be moved from one place to another for its intended use. Most of these systems are expensive, inefficient, and distract from the aesthetic appeal of the structures on which they are employed.
Another form of energy conversion is direct sunlight-to-electrical energy conversion units, primarily silicon cells. While these devices do work, they are quite inefficient, very expensive, and perform poorly except in bright direct sunlight. Their application for economic usage has, therefore, been quite limited.
Primarily there are two basic types of solar energy systems, and a combination of these two systems. The first type is the active system, mainly described above. It has evolved that the second type, or passive solar energy system, is exceedingly the most efficient; however, there are many drawbacks to these systems, including the lack of control of heating which produces overheating at times when the sun is most available, and a problem of not being able to reject the heat during periods when heating is not desired. A third type, the hybrid system, makes use of the passive collecting of heat, which is the direct collecting of heat through an aperture and the storage of that heat in some medium, such as a mass of building materials, including masonry and concrete, or in the use of phase-change materials. Even in the hybrid system, there is a lack of control, and there is no known system available which can control solar heating efficiently and effectively and be able to reject the heating when it is undesirable within short time intervals.
It is the object of this invention to provide a new and improved system of controlling the quantity of radiation entering a building, the direction of transmission of it within the building, and the absorption of it.